import math
import random
import numpy as np


print("hello world")
a = math.sin(0.5)
print(a)
b = np.array((1, 2, 3, 4))
print(b)


def main():
    if __name__ == '__main__':
        print('This program is run directly')
    elif __name__ == 'hello_python':
        print('This program is used as a module')

main()

 